The Paleo Diet - Loren Cordain [28]
Finally, if you eat more carbohydrates, you’re eating less protein. Protein is the dieter’s friend: it reduces your appetite and increases your metabolism—and this translates rapidly into weight loss.
One of the great dietary myths in the Western world is that whole grains and legumes are healthful. The truth is that these foods are marginal at best. But what about the “health-food” breads? At best, they’re less bad than the overprocessed, super-refined white breads you could be buying. But they’re still not part of the Paleo Diet. Formerly (before “progress” brought refined milling technology to bread making), almost all cereal grains either were eaten whole or were so crudely milled that nearly the entire grain—bran, germ, and fiber—remained intact, and flour was much less refined than the kind we buy today. Our great-greatgrandparents ate cracked wheat breads and baked goods with a moderate glycemic index—which meant a more moderate rise in blood sugar level.
Does this mean that whole grains are good for you? Not necessarily. It just means that an extra bad characteristic—a high glycemic index—wasn’t incorporated into them yet. That unfortunate addition happened about 130 years ago, when steel roller mills came on the flour-making scene. They smashed all the fiber out of the grains and left the wimpy white, high-glycemic powder most of us think of as flour. Today, almost all baked goods made with this stuff frequently cause the blood sugar level to rise excessively.
Even “whole wheat” bread made from flour ground by these steel roller mills does the same thing to your blood sugar, because the flour particle size is uniformly small—so it’s virtually no different from white flour. About 80 percent of all the cereal products Americans eat—as they follow the directions of the USDA Food Pyramid—come from refined white flour with a high glycemic index.
Cereal grains are literally best left for the birds
Compounding the Problem: Sugar and Sweeteners
Our Paleolithic ancestors loved honey. But it was a rare treat, because it was only available seasonally and in limited quantities (and they had to outmaneuver bees to get it). So for the most part, refined sugars—another source of carbohydrates—simply were not part of humanity’s diet for 2.5 million years. In fact, until about the last 200 years or so, they weren’t part of anybody’s diet.
Sugar is another of those side effects of technological “progress,” and its rise to prominence in our daily life has been rapid. In England in 1815, the average person used about 15 pounds of table sugar a year; in 1970, the average person used 120 pounds. How much sugar do you buy a year? Do you buy another 5-pound bag every time you go to the grocery store? You’re not alone.
Yet sugar, like refined cereal grains, is not good for us. Sure, it causes cavities—most of us hear that message every time we go to the dentist. But it’s also becoming evident that sugar poses more serious health problems. It promotes insulin resistance and metabolic syndrome diseases almost as much as high-glycemic breads and starchy potatoes do.
The chemical name for table sugar is “sucrose.” Although sucrose has nearly the same high glycemic index (65) as white bread (70), it has two additional characteristics that make it particularly harmful for insulin metabolism. First, it is 100 percent carbohydrate, meaning that its glycemic load is very high.
Second, when your body digests sucrose, it is broken down into two simple sugars—high-glycemic glucose (with a glycemic index of 97) and low-glycemic fructose (with a glycemic index of 23). Scientists used to think that fructose was not harmful because of its low glycemic index. But recent laboratory studies by Dr. Mike Pagliassotti and colleagues at Arizona State University have revealed that fructose is actually the main culprit in table sugar that causes insulin resistance.